Colorblind persons have an inability to perceive differences between some of the colors that other people can distinguish. For example, persons with normal color vision may have three types of cone cells within their retinas, and may be referred to as trichromats. Colorblind persons, on the other hand, may have only two types of cone cells within their retinas, and may be referred to as dichromats.
It may not be trivial for persons with normal vision (trichromats) to design visuals that are equally suitable for colorblind as well as non-colorblind viewers. For example, if a trichromatic user were to design a visual, such as a subway map, such a map might be illustrated with a green route and a red route. While such a green route and a red route might be useful for a trichromatic user, they may be less than helpful to a dichromatic user in differentiating between the two routes. More specifically, for a dichromatic user with a red-green-type colorblindness, such a green route and a red route might appear to be substantially of the same color.
Reference is made in the following detailed description to the accompanying drawings, which form a part hereof, wherein like numerals may designate like parts throughout to indicate corresponding or analogous elements. It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, it is to be understood that other embodiments may be utilized and structural and/or logical changes may be made without departing from the scope of claimed subject matter. It should also be noted that directions and references, for example, up, down, top, bottom, and so on, may be used to facilitate the discussion of the drawings and are not intended to restrict the application of claimed subject matter. Therefore, the following detailed description is not to be taken in a limiting sense and the scope of claimed subject matter defined by the appended claims and their equivalents.